If you are assessing a long-length folder, then Variobend may very well be among the manufacturers that catch your attention. Variobend’s single folder series has been developed specifically for bending long sheets, flashing, and architectural profiles precisely and effectively. However, selecting the right machine involves taking into account working lengths, controls, and options that are available.

In this article, we’ll break down the key Variobend single folder specifications, capacities, and options, while comparing them with purpose-built long folding solutions from BMS Machinery. You’ll gain the technical information needed to evaluate machines and choose the right configuration for your production requirements.

What Is a Variobend Single Folder?

The Variobend single-folder system employs a single angled bending beam, referred to as an apron, for bending sheet metal. The Variobend system patents the tilting of the apron at an angle rather than upwards, allowing for extra working space that the vertical beam folder does not have. It is the extra space provided by the design that enables the folder to bend profiles that a regular vertical beam folder cannot handle.

You'll typically find these machines running long panels for:

• Roofing and cladding profiles: ridge caps, gutters, and flashings that need consistent bends across several meters. 

• Architectural sheet metal: custom trim and fascia where every bend has to match the last one exactly. 

• HVAC ductwork: long, straight-run panels that need clean, repeatable folds.

Variobend Single Folder Specifications 

Here's where the buying decision actually gets made. Specs vary by model and length, but the ranges below reflect what you'll typically see across the Variobend single-folder lines. 

• Working length: Variobend single folders come in various lengths ranging from 4 to 12 m and hence can be fitted with machines according to your longest standard panels.

• Bending capacity: Working capacity will vary from 1.5 mm to 2.0 mm for mild steel (St. 37). Bending capacity reduces in case of hard material such as stainless steel, and hence it's always necessary to refer to the manufacturer's chart.

• Clamping beam opening height: The opening height of the clamping beam is around 770 mm and hence provides sufficient space for turning a plate when required within the machine.

• Back gauge depth: The back gauge is usually electric, ball screw driven, and has a working depth of 5 to 1,000 mm and, in some machines, 1,250 mm.

• Control system: The control system is a touch screen-based one. It does profile programming, stores a shape library, and accepts DXF files.

• Bending beam construction: Segmented, high-strength steel beams with replaceable hardened inserts hold their precision across the full working length, even after years of heavy use.

For comparison, BMS's own 8M Long Folder Slitter runs an 8,000 mm working length with a bending range of 0 to 125 degrees, and it's built around a similar philosophy: a fully welded, high-tensile steel frame (32 mm thick at the arm pivots) paired with a Schneider PLC touchscreen control for fast profile programming.

Capacity by Material Type 

Capacity numbers vary greatly based on what is being processed through the machine, and that is usually the spec that gets consumers into trouble. If a machine is rated for 2.0 mm mild steel, that doesn't necessarily mean it will be able to bend that thickness of stainless steel, as stainless hardens faster than mild and causes more stress on the bending beam and segment.

As a general rule of thumb across single-folder machines in this class:

• Mild steel: The widest capacity rating, generally up to 2.0 mm and possibly more on beefier machines.

• Stainless steel: Capacity number usually goes down to 1.5 mm or less, as stainless is tougher and stresses the tools more.

• Aluminum: Capacity goes higher, up to 3.0 mm or more, as aluminum bends more easily, but thin aluminum can scuff when clamps need maintenance.

BMS's 8M Long Folder Slitter is rated for mild steel at 0.4 to 2 mm, stainless steel at 0.4 to 1.5 mm, and aluminum at 0.4 to 3 mm; a spread that lines up closely with what you'd expect from a Variobend-class machine, and gives you a concrete benchmark to compare against any quote you're reviewing.

The takeaway: always ask for capacity figures broken out by material, not a single blanket number. If a spec sheet just says "up to 2mm" without naming the material, ask which one before you buy.

Key Options and Add-Ons 

The base machine gets you bending. These options are what determine how well it fits your actual jobs, so it's worth going through each one and asking honestly whether your shop needs it.

• Replaceable hardened clamp inserts: This isn’t really an “option,” but something that any folder should have. The clamp beam absorbs most of the wear during each and every operation, and replaceable clamp inserts instead of entire beam replacements save huge amounts of money over time. Customizable radii of inserts allow you to change from multi-angle, circular, and conical bending without molds. This option is incorporated in the 8M Long Folder Slitter by BMS.

• Servo-driven crowning system: Servo crown control system. While bending long sheets, the center of the sheet usually bends too much compared to the edges; this phenomenon is referred to as deflection. A servo crown system automatically moves each stand to eliminate it. Manually controlled crown does its job perfectly well when used on shorter machines, but once you need to process sheets longer than 6 or 8 meters, servo crown pays for itself fast.

• Slitting attachment: If trimming the width of your sheets prior to folding is something you need to do, then an attached slitter will be helpful. Make sure it uses replaceable hardened inserts made of materials such as Cr12MoV.

• Conical bending and slotting: Great for custom architectural work that involves tapered flashing. If your business involves straight run gutters and standard profiles, this is probably not something you will need; but if you’re doing custom architectural work, it's worth paying extra for.

• Touchscreen control with profile library: Not only does this make things easier for you, but it will help save time during changeovers; the more often you do them, the better.

• Safety guarding:  Light curtains and guarded operating areas come as standard in all modern folder machines, due to the high level of force used.

Single Folder vs. Double Folder: Which One Fits Your Shop? 

This is the point of choice that most customers reach even before getting to the point of brand comparison.

The single folder has only one curve. It’s easier to use, usually cheaper, and perfect for those extended jobs such as gutters, flashing, and common roofing trim work where there isn’t much flipping of the panels during the process.

The double folder, also referred to as the up-and-down folder, has two curves and doesn’t require any turning of the sheet by the user. This is a great time-saver when there are many bends made in opposite directions; it’s also more costly.

Here's a quick way to think about it: if most of your jobs are long, straightforward profiles with bends running the same way, a single folder does the job at a lower cost. If you're regularly producing complex parts with bends in two directions, and flipping the sheet by hand is eating into your cycle time, the double folder's extra cost pays for itself in labor saved. BMS's Double Bending Slitter Folder is built for exactly that second scenario, if it turns out to be the better fit for your production mix.

How to Choose the Right Variobend Single Folder Length and Capacity 

Once you’ve decided that a Variobend single folder fits your production needs, selecting the right model comes down to several practical factors:

• Match the working length to your largest panels: Get a machine that will accommodate the largest panel that you need today, with some extra capacity to ensure future order flexibility. It is easy to get tied up buying to your exact current needs but may be restrictive in production down the road.

• Check capacity against your heaviest material: Size the machine based on your hardest or most challenging material to work, rather than the average jobs that you do. If you occasionally need 2 mm stainless steel bending, you may need more capacity than just a machine built to handle 1.2 mm mild steel.

• Evaluate the back gauge depth: Make sure the back gauge depth is suitable. The back gauge depth specification is often overlooked but may turn out to be an important factor once the machine is installed.

• Consider your changeover frequency:  If you switch from one profile to another multiple times a day, look carefully at your controls, tooling layout, and segment changeover procedure.

• Allow enough floor and handling space: There is more to space requirements than just the working length of the machine. Longer panels will require sufficient clearance for loading, unloading, placement, and material handling at both ends of the machine.

• Consider operator experience: Operators with previous experience do not necessarily require any automation or advanced controls. However, if you change your operators frequently, then having an easy-to-use touch screen panel with pre-programmed bending programs could help.

Maintenance and Longevity Considerations 

Specifications and features are important when comparing a Variobend single folder. However, you have to think about the performance of this machinery for several years after its installation as well. Long folders have a high degree of wear on the clamping beam and bending elements since they take part in every bending operation.

Before buying, pay close attention to the following:

• Replaceable segments vs. solid beam: Make sure that worn-out segments are replaceable rather than the whole bending beam, as this will reduce repair expenses in the long run.

• Frame construction: Having a sturdy high-tensile steel frame that is fully welded together ensures minimum deflection of the machine and accuracy of the bends produced over time.

• Hydraulic system access: Ask the dealers or experienced technicians about accessibility of hydraulic components for servicing and repair work. Ask dealers or technicians with hands-on experience with the specific Variobend model about the actual maintenance process.

Conclusion

Whatever machine you find yourself on, whether it be a Variobend single folder or something else similar, the figures that you want to pay attention to are always the same: working length to accommodate your largest panels, capacity for your largest materials, and controls to run the machine without much hassle.

If you'd like to see how BMS's long folder slitter and double bending slitter models stack up against a Variobend spec sheet for your specific jobs, get in touch with our team for a capacity comparison built around your material and panel sizes.

FAQs

What's the maximum sheet length a Variobend single folder can handle?

The standard Variobend single apron/single folder can have a maximum sheet working length of 12 meters (about 39 feet or 4 light-duty increments up to 12m/21-25ft for particular regional single-folder variations such as 21 feet / 6.4m to 12m maximum).

What material thickness can a single folder bend?

The standard sheet metal folder is capable of bending material thicknesses between 0.5 mm and 3.0 mm (0.02 to 0.12 inches), depending on the size of the machine.

What's the difference between a single folder and a double folder?

The single folder will have one storage compartment for documents inside, whereas the double folder will have two compartments or clips to hold documents inside.

Do single folders need a separate slitter, or can it be built in?

Yes, slitting can be incorporated directly into most single folders and paper folding machines by use of rotary slitter blade assemblies, although heavy-duty ones usually operate separately.

Can a single folder handle stainless steel and aluminum, or just mild steel?

Yes, a single sheet metal folder is capable of handling mild steel, stainless steel, and aluminum, but it is important to lower the maximum thickness limit for the harder metals.